Process for making inner liners for tires.



B. S. ESHBLMAN. PROCESS FOR MAKING INNER LINERS FOR TIRES.

APPLICATION FILED I'EB.13. 1909.

Patented Dec. 28, 1909.

UNITED STATES PATENT OFFICE.

BRENT S. ESHELMAN, OF ASHLAND, OHIO, ASSIGNOR TO GUY V. KRICHBAUM, 0FASHLAND, OHIO.

PROCESS FOR MAKING INNER LINERS FOR TIRES.

To all whom it may concern:

Be it known that I, BnnN'r S. ESIIELMAN, a citizen of the United States,residing at Ashland, in the county of Ashland and State of Ohio, haveinvented a certain new and useful Improvement in Processes for MakingInner Liners for Tires, of which the following is a full, clear, andexact descrip tion, reference being bad to the accompanying drawings.

My invention relates to a process for the manufacture of an inner linerto be used in connection with vehicle tires, the same being adapted tobe placed within the outer shoe of the tire.

The process comprises the several steps set forth in the specificationand mentioned in the claims.

Reference should be had to the accompanymg drawings, in whichlgure l isa perspective view of the several plies of material used in making theliner; Fig. 2 is a perspective view showing a portion of a form used inshaping the liner;

ig. 3 is a view of the completed liner.

It has been a. problem in the tire art to secure an inner liner fortires which, while being strong and durable would at the same time givethe desired and necessary flexibility, so that the liner might conformto the distortions of the tire and not be so stiff as to crack. Theherein described process roduces an inner liner for tires which providesdurability as well as flexibility.

In the first steps in the process of manufacture, suitable strips ofabsorbent flexible material, such as duck, canvas, or analogous materialare prepfiedvfhese'stripsare cut of a width suitable for the size ofliner to be manufactured and of the proper len th for the diameter ofthe tire with which they are to be used. In Fig. 1 three plies are shownassociated together, but it will be evident that a greater or lessnumber may be used if desired. The strips are out upon a biaswithrespect to the direction of the threads of the material and when thestrips are in assembled position, the adjacent strips have the threadsor fibers extending in different directions. As shown in this figure,the lower pl 1 is quite broad, the ply 2 above ply 1 is much narrower,and 1y 3 which is on top is wider than ply 2 and narrower than ply 1.

Specification of Letters Patent.

Application filed February 13, 1909.

Patented Dec. 28, 1909. Serial No. 477,658.

These particular relative widths are chosen inasmuch as it is found thatthey give a very satisfactory result when made into the finishedarticle, but it is not intended to limit the invention to the preciserelative widths or particular method of assembling.

The strips when properly cut are impreg nated with a rubber solution andare then placed one upon the other in their proper relative position.The next step is to sub jcct the associated strips to suitable heat,whereby the rubber with which they have been previously impregnatedbecomes very soft and gununy. They are then ru n thr0ugh a )fil1 ()frolls which exert considerable presanemia roll the strips so'that theyadhere very closely together and become substantially one piece. Due tothe pressure, the rubber is forced into the interstices between thestrands of fabric in each of the strips.

\Vhile the rubber is still in a soft and pliable condition the liner isplaced upon a form, one variety of which is illustrated in Fig. 2. Theform shown in Fig. 2 is simply illustrative of any desired form andwhere desired a mold may be used with equal fa cility. In this step ofthe process the liner is given a shape corresponding to the diameter andwidth of tire with which the liner is adapted to be used. Nhen properlyassembled with relation to the form, the liner and form are next placedwithin a steam tight oven or box and are there subjected to steam at asuitable pressure and for a suitable length of time. The liners areremoved from the vulcanizing oven before they are completely cured,resulting in a liner in what is technically known as semi-curedcondition. This will leave the liner in a pliable and flexiblecondition; however, care is taken to carry the vulcanizing suflicientlyfar so that the rubber is not too sticky. The liners are next coatedupon their exterior surface with a rubber solution prepared for quickvulcanizing. This coat of rubber solution may be placed upon the linerimmediately after being taken from the oven or at any time thereafter,as may be desirable.

The liner which results from the rocess above described is very toughand urable and is very flexible, which are the points desired in sucharticles of manufacture.

As before stated, the liner is designed to be used Within the shoe of avehicle tire. The liner, being placed within the shoe of the vehicletire and being subjected to the heat which is generated as the tirepasses over the road, when the tire is in use, will become vulcanized tothe inner surface of the outer shoe, due to the fact that the outersurface of the liner is coated with a solution of rubber speciallyprepared with a purpose of securing quick vulcanizing. In this mannerthe inner liner becomes fastened to the shoe, practically becoming anintegral part thereof. This does not destroy or atfect the resiliency ofthe tire, for the reason that the inner liner is perfectly flexible andso conforms to all the distortions of the tire. This feature offlexibility is secured by the semicuring of the liner and would notresult if the liner were entirely cured, for under the heat generated inthe tire, a liner which was entirely cured would become stifi andnonfiexible and would shortly become disconnected from the shoe and ofno value whatsoever.

The inner liner by becoming fastened to the shoe is a very eflicientstrengthening member for the shoe and holds the walls together eventhough a split or cut occur in the shoe. Furthermore, this inner linerprevents the passage of puncturing particles through the same andthereby forms a protection for the inner tube where such is used.

It is often desirable to place a layer of rubber compound upon theexterior and interior of the liner, or in fact between the variouslayers of the liner. In such a case, this rubber compound is appliedbefore semicuring. The liner is then placed under considerable pressurein any suitable manner while being subjected to heat to semi-cure thesame. Such treatment as above set forth produces a liner of morefinished appearance and also results in a stronger and more durablearticle, for the various plies are securely held together by theinterposed layers of rubber.

Having thus described my invention, What I claim is:

I. The herein described process, which consists in impregnating a pieceof flexible material with suitable rubber solution, semicuring the same,and then coating the material with a solution of rubber suitablyprepared for vulcanizing.

2. The herein described process, which consists in subjecting aplurality of strips of flexible material to a suitably prepared rubbersolution, heating the same and subjecting the plies to ressure to causethem to adhere to each ot er, and subjecting the stri s to steam for asuitable period of time so t at the are semi-cured.

3. The erein described rocess, which consists in subjecting a pluralityof strips of flexible material to a suitably prepared rubber solution,heating the same and subjecting the plies to pressure to cause them tosubjecting the strips to seam or a suitable period of time so that theyare semi-cured, and coating the strips with a solution of rubbersuitably prepared for quick vulcanizing.

at. The process of manufacturin inner liners to tires which com a stripof; absorbent flexible material of a suitable width and length,impregnating the same with a rubber solution, forming the said strip tothe proper shape for the size of tire with which the liner is to beused, and subjecting the formed strip to a vulcanizing process until thestrip is semi-cured.

5. The herein described process of manufacturing inner liners for tires,which consists in preparing strips of absorbent flexible material ofproper length and width, impregnating the said strips with a suitablyprepared rubber solution, subjecting the strips to pressure whereby theyadhere to each other, forming the said strips over a. form or in a moldto give the desired shape foriliet'ifigWvith which the liner is to beused, and subjecting the formed strip to a vulcanizing process until thesame is semicured.

6. The herein described process of manufacturing inner liners for tires,which consists in preparing strips of absorbent flexible material ofproper length and width,

impregnating the said strips with a suit ably prepared rubber solution,subjecting the strips to pressure whereby they adhere to each other,forming the said strips over a form or in a mold to give the desiredshape for the tire with which the liner is to be used, subjecting theformed strip to a vulcanizing process until the same is semicured, andcoating the outer surface of the said liner with a solution of rubbersuitably prepared for quick vulcanizing.

7. As a new article of manufacture an inner liner for tires comprising apiece of a on material impregnated with rubber which is semi-cured.

8. As a new article of manufacture, an inner liner for tires, comprisinga piece of absorbent flexible material impregnated with rubber which issemi-cured, the outer surface of the liner being coated with a solutionof rubber suitably prepared for vulcanizing.

9. As a new article of manufacture, an inner liner for tires com risinga plurality of superimposed stri s of absorbent flexible materialimpregnate with rubber which is semi-cured.

10. As a new article of manufacture, an inner liner for tires comprisinga plurality of superimposed strips 0 absorbent flexible materialimpregnated with rubber which is semi-cured, the outer surface of theliner being coated with a solution of rubber suitably prepared forvulcanizing.

11. As a new article of manufacture, an inner liner for tires comprisinga plurality of superin'iposed strips of absorbent flexible material,said strips being out upon the bias,

Witnesses VVILLIAM T. Devon, C. F. BENNER.

